:root {
  --navy: #0f3d5e;
  --navy-dark: #0a2a42;
  --teal: #1fb5a8;
  --amber: #f6a623;
  --coral: #ef6f5e;
  --violet: #6c63ff;
  --ink: #1d2733;
  --muted: #5b6878;
  --line: #e3e8ee;
  --bg-alt: #f5f8fb;
  --radius: 18px;
  --shadow: 0 10px 30px rgba(15, 61, 94, 0.08);
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial,
    "PingFang SC", "PingFang TC", "Hiragino Sans GB", "Microsoft YaHei", "Microsoft JhengHei",
    "Noto Sans SC", "Noto Sans TC", sans-serif;
}

html:lang(zh-Hant) { --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang TC", "PingFang HK", "Microsoft JhengHei", "Noto Sans TC", sans-serif; }
html:lang(zh-Hans) { --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif; }

*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 80px; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  line-height: 1.65;
  background: #fff;
  -webkit-font-smoothing: antialiased;
}

img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
h1, h2, h3 { line-height: 1.25; margin: 0 0 0.5em; }
p { margin: 0 0 1em; }

.container { width: min(1140px, 100% - 40px); margin-inline: auto; }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}
.header-inner { display: flex; align-items: center; gap: 24px; height: 68px; }
.brand { display: flex; align-items: center; gap: 10px; }
.brand-text { display: flex; flex-direction: column; line-height: 1.15; }
.brand-name { font-weight: 800; font-size: 1.15rem; color: var(--navy); }
.brand-sub { font-size: 0.75rem; color: var(--muted); }

.nav { display: flex; gap: 28px; margin-left: auto; }
.nav a { font-weight: 500; color: var(--muted); transition: color 0.2s; }
.nav a:hover { color: var(--navy); }

.header-actions { display: flex; align-items: center; gap: 12px; }
.lang-switch { display: flex; background: var(--bg-alt); border-radius: 999px; padding: 3px; }
.lang-switch button {
  border: 0;
  background: transparent;
  font: inherit;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--muted);
  padding: 5px 11px;
  border-radius: 999px;
  cursor: pointer;
}
.lang-switch button.active { background: var(--navy); color: #fff; }

.nav-toggle { display: none; border: 0; background: none; padding: 8px; cursor: pointer; }
.nav-toggle span { display: block; width: 22px; height: 2px; background: var(--ink); margin: 5px 0; transition: transform 0.2s, opacity 0.2s; }
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* Buttons */
.btn {
  display: inline-block;
  padding: 13px 26px;
  border-radius: 999px;
  font-weight: 600;
  transition: transform 0.15s, box-shadow 0.2s, background 0.2s;
  text-align: center;
}
.btn:hover { transform: translateY(-1px); }
.btn-primary { background: var(--amber); color: var(--navy-dark); box-shadow: 0 6px 18px rgba(246, 166, 35, 0.35); }
.btn-primary:hover { background: #ffb63f; }
.btn-ghost { border: 2px solid rgba(255, 255, 255, 0.5); color: #fff; }
.btn-ghost:hover { background: rgba(255, 255, 255, 0.1); }
.btn-block { display: block; width: 100%; }

/* Hero */
.hero {
  background: radial-gradient(circle at 85% 20%, rgba(31, 181, 168, 0.35), transparent 45%),
    linear-gradient(135deg, var(--navy-dark), var(--navy) 60%, #145a7a);
  color: #fff;
  padding: 80px 0 40px;
  overflow: hidden;
}
.hero-inner { display: grid; grid-template-columns: 1.15fr 1fr; gap: 40px; align-items: center; }
.hero h1 { font-size: clamp(2.2rem, 5vw, 3.6rem); font-weight: 800; letter-spacing: -0.01em; }
.hero .lead { font-size: 1.15rem; color: rgba(255, 255, 255, 0.82); max-width: 560px; }
.hero-cta { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 28px; }

.eyebrow { text-transform: uppercase; letter-spacing: 0.12em; font-size: 0.8rem; font-weight: 700; color: var(--teal); margin-bottom: 12px; }
.hero .eyebrow, .eyebrow-light { color: #7fe3d9; }

.hero-visual { display: flex; justify-content: center; }
.orbit { position: relative; width: min(400px, 100%); aspect-ratio: 1; }
.orbit::before {
  content: "";
  position: absolute;
  inset: 8%;
  border-radius: 50%;
  border: 1px dashed rgba(255, 255, 255, 0.2);
}
.route { position: absolute; inset: 0; width: 100%; height: 100%; }
.route path { animation: dash 18s linear infinite; }
@keyframes dash { to { stroke-dashoffset: -320; } }

.bubble {
  position: absolute;
  width: 84px;
  height: 84px;
  border-radius: 24px;
  display: grid;
  place-items: center;
  font-size: 2rem;
  font-weight: 800;
  color: #fff;
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.25);
  animation: float 6s ease-in-out infinite;
}
.bubble-en { background: var(--coral); top: 12%; left: 6%; }
.bubble-zh { background: var(--teal); top: 46%; left: 56%; animation-delay: -2s; }
.bubble-math { background: var(--violet); bottom: 6%; left: 22%; animation-delay: -4s; }
@keyframes float { 50% { transform: translateY(-12px); } }

.hero-stats {
  list-style: none;
  padding: 0;
  margin: 56px 0 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
.hero-stats li {
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: var(--radius);
  padding: 20px 22px;
}
.hero-stats strong { display: block; font-size: 1.5rem; color: var(--amber); }
.hero-stats span { color: rgba(255, 255, 255, 0.8); font-size: 0.95rem; }

/* Sections */
.section { padding: 96px 0; }
.section-alt { background: var(--bg-alt); }
.section-head { max-width: 720px; margin-bottom: 48px; }
.section-head h2 { font-size: clamp(1.8rem, 3.5vw, 2.5rem); color: var(--navy); }
.section-lead { font-size: 1.08rem; color: var(--muted); }

/* About */
.pillars { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.pillar {
  padding: 36px;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
}
.pillar h3 { font-size: 1.3rem; color: var(--navy); }
.pillar p { color: var(--muted); margin: 0; }
.pillar-icon, .platform-icon {
  width: 52px;
  height: 52px;
  border-radius: 14px;
  background: rgba(31, 181, 168, 0.12);
  display: grid;
  place-items: center;
  margin-bottom: 18px;
}
.pillar-icon svg, .platform-icon svg {
  width: 26px;
  height: 26px;
  stroke: var(--teal);
  fill: none;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* Products */
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.card {
  background: #fff;
  border-radius: var(--radius);
  padding: 32px;
  box-shadow: var(--shadow);
  border-top: 5px solid var(--accent);
  transition: transform 0.2s, box-shadow 0.2s;
}
.card:hover { transform: translateY(-4px); box-shadow: 0 18px 40px rgba(15, 61, 94, 0.12); }
.card-en { --accent: var(--coral); }
.card-zh { --accent: var(--teal); }
.card-math { --accent: var(--violet); }
.card-badge {
  width: 56px;
  height: 56px;
  border-radius: 16px;
  background: var(--accent);
  color: #fff;
  font-size: 1.5rem;
  font-weight: 800;
  display: grid;
  place-items: center;
  margin-bottom: 20px;
}
.card h3 { font-size: 1.35rem; color: var(--navy); }
.card p { color: var(--muted); }
.tags { list-style: none; padding: 0; margin: 0; display: flex; flex-wrap: wrap; gap: 8px; }
.tags li {
  font-size: 0.82rem;
  font-weight: 600;
  padding: 4px 12px;
  border-radius: 999px;
  background: color-mix(in srgb, var(--accent) 12%, white);
  color: color-mix(in srgb, var(--accent) 80%, black);
}

.platforms { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; margin-top: 32px; }
.platform {
  display: flex;
  gap: 18px;
  align-items: flex-start;
  background: #fff;
  border-radius: var(--radius);
  padding: 26px 28px;
  border: 1px solid var(--line);
}
.platform-icon { flex: none; margin: 0; }
.platform h3 { font-size: 1.1rem; color: var(--navy); margin-bottom: 4px; }
.platform p { color: var(--muted); margin: 0; }

/* Schools */
.scenes { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; margin-bottom: 48px; }
.scene {
  padding: 32px;
  border-radius: var(--radius);
  background: linear-gradient(135deg, rgba(31, 181, 168, 0.1), rgba(15, 61, 94, 0.05));
}
.scene h3 { color: var(--navy); font-size: 1.25rem; }
.scene p { color: var(--muted); margin: 0; }

.steps {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  counter-reset: step;
}
.step { position: relative; padding: 24px; border-radius: var(--radius); border: 1px solid var(--line); }
.step-num { font-size: 2rem; font-weight: 800; color: var(--amber); display: block; margin-bottom: 8px; }
.step h3 { font-size: 1.1rem; color: var(--navy); }
.step p { color: var(--muted); margin: 0; font-size: 0.95rem; }

/* Contact */
.contact { background: linear-gradient(135deg, var(--navy-dark), var(--navy)); color: #fff; }
.contact h2 { font-size: clamp(1.8rem, 3.5vw, 2.5rem); }
.contact .section-lead { color: rgba(255, 255, 255, 0.8); }
.contact-inner { display: grid; grid-template-columns: 1.2fr 1fr; gap: 48px; align-items: center; }
.contact-card { background: #fff; color: var(--ink); border-radius: var(--radius); padding: 32px; box-shadow: 0 20px 50px rgba(0, 0, 0, 0.25); }
.contact-card dl { margin: 0 0 24px; display: grid; gap: 18px; }
.contact-card dt { font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.08em; color: var(--muted); font-weight: 700; }
.contact-card dd { margin: 2px 0 0; font-weight: 600; color: var(--navy); }
.contact-card dd a:hover { color: var(--teal); }

/* Footer */
.site-footer { background: var(--navy-dark); color: rgba(255, 255, 255, 0.65); padding: 28px 0; font-size: 0.9rem; }
.footer-inner { display: flex; justify-content: space-between; align-items: center; gap: 16px; flex-wrap: wrap; }
.footer-inner p { margin: 0; }
.brand-footer { color: #fff; font-weight: 600; }

/* Reveal on scroll */
.reveal { opacity: 0; transform: translateY(20px); transition: opacity 0.6s, transform 0.6s; }
.reveal.visible { opacity: 1; transform: none; }

/* Responsive */
@media (max-width: 960px) {
  .hero-inner { grid-template-columns: 1fr; }
  .hero-visual { display: none; }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .card { padding: 26px 22px; }
  .contact-inner { grid-template-columns: 1fr; }
}

@media (max-width: 760px) {
  .nav {
    position: absolute;
    top: 68px;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: #fff;
    border-bottom: 1px solid var(--line);
    padding: 8px 20px 16px;
    display: none;
  }
  .nav.open { display: flex; }
  .nav a { padding: 12px 0; border-bottom: 1px solid var(--line); }
  .nav-toggle { display: block; }
  .header-actions { margin-left: auto; }
  .brand-sub { display: none; }
  .hero { padding-top: 56px; }
  .hero-stats, .pillars, .cards, .platforms, .scenes, .steps { grid-template-columns: 1fr; }
  .section { padding: 72px 0; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .route path, .bubble { animation: none; }
  .reveal { opacity: 1; transform: none; transition: none; }
}